PRACTICE. 251 



Combining, we obtain 



Series I, II 34 Det., 14 85529. Mean 89.95 



" III, IV, V 23 Det., 14 78 ; 36. 88 



Mean of all, 57 Det., 14 78536. " 89.91 



Actual extremes are : 



Highest, Series II. 90.14 mgr. 

 Lowest, IV. 89.78 " 

 Absolute Range, 0.36 te 



The actual range of the weights of one liter of hydrogen 

 is, therefore, a little over 



one third of a milligramme, 



which is exactly one hundred times the weight of the last 

 gnat strained out by Morley. Page 249, supra. 



Of course, such straining may strain the strongest man. 

 It has affected Mr. Morley seriously and induced the Morbus 

 Stasii. 



But we must close this subject. We shall here give the 

 general mean of all determinations, the extreme means of a 

 single series, and the actual extremes of the entire work. 



Weight of Liter in Mgr. Hydrogen. Oxygen. 



Absolute lowest, 89.78 1428.3 



Lowest mean, 89.87 1428.8 



Mean of all, 89.91 1429.0 



Highest mean, 89.97 1429.2 



Absolute highest, 90.14 1429.6 



Absolute Range, 0.36 1.3 



Uncertainty, one in 250 1 100 



These are the actual facts. The total range actually 

 covered does not necessarily include the truth. We remem- 

 ber, that almost all coins actually weighed were light so 

 also, all -weight of a liter of a given gas may be either light 

 or heavy j as compared to the actual range of weight, accord- 

 ing as there may lurk a trace of a lighter or heavier gas, in 

 the supposedly pure gas ! 



Now, we do know heavier gases that no means of purifi- 

 cation used by Morley could have removed such as argon. 

 On burning the hydrogen to water, the argon would remain 

 dissolved in the water, under the exact conditions used in 

 Morley's complete synthesis of water. 



